The present invention relates to devices for managing body fluids such as urine, sweat, saliva, blood, menses, purulence, or fecal material, and in particular to their ability to acquire and retain aqueous based materials. The invention further relates to disposable absorbent articles such as baby diapers or training pants, adult incontinence products, and feminine hygiene products and other body liquid handling articles such as catheters, urinals, and the like.
The invention further relates to devices for managing body liquids comprising a liquid handling member having high suction and high permeability.
Devices for managing body fluids are well known in the art and are frequently used for a wide variety of purposes. For example, the devices serve hygienic purposes such as diapers, sanitary napkins, adult incontinence products, underarm sweat pads, and the like. There is another class of such devices which serve medical purposes such as wound dressings or drainages, catheters, and the like. Accordingly such devices have been designed to cope with a large variety of different body liquids such as for example urine, sweat, saliva, blood, menses, purulence, fecal material, and the like.
The ability to provide better performing devices such as diapers has been contingent on the ability to develop relatively thin absorbent cores or structures that can acquire and store large quantities of discharged body fluids, in particular urine.
In addition, it is preferred to provide structures having a low capacity in the regions between the legs of the wearer such as in PCT application U.S. Ser. No. 97-05046, filed on Mar. 27, 1997, relating to the movement of fluid through certain regions of the article comprising materials having good acquisition and distribution properties to other regions comprising materials having specific liquid storage capabilities.
Most of the absorbent articles comprise therefore at least one fluid handling member that is designed for quickly acquiring and/or transporting liquid away from the loading point.
Examples of suitable liquid transport members based on crosslinked and curled cellulose are disclosed in European patent application No. 0 512 010 (Cook et al.). Further examples of suitable liquid transport members having high vertical liquid transport rates are disclosed in European patent application No. 0 809 991 (Schmidt et al.). Other suitable liquid transport members based on HIPE foams are disclosed in U.S. patent application Ser. No. 09-042418 (DesMarais et al., PandG case 7051).
Example structures comprising liquid transport members to transport liquid out of the crotch region are disclosed in PCT patent application WO 98/43580 (LaVon et al.).
Whilst such liquid transport members have been designed with capillary transport mechanisms in mind, thus aiming at positioning materials with smaller capillaries and/or increased hydrophilicity closer to the ultimate storage material, and materials with larger pores and less hydrophilicity closer to the loading zone, it has in addition been recognized, that acquisition/distribution materials have the tendency to not only transport the fluid, but also to retain the liquid, which can result under specific conditions to undesired effects, such as rewet or reduced fluid acquisition and/or distribution performance, which is particularly pronounced for acquisition/distribution materials being designed to balance acquisition and distribution properties.
Accordingly, liquid storage members have been developed, which have an improved balance of the fluid handling properties such that well performing acquisition/distribution materials or members can be dewatered efficiently by the storage materials or members. This is typically achieved by fluid storage materials or members having a high liquid suction capability.
In PCT patent application No. U.S. Ser. No. 98105044 (Palumbo et al.), absorbent structures are disclosed which comprise materials exhibiting a high liquid suction capability. These materials disclosed by the prior art employ small capillaries such as obtained by a small capillary HIPE foam, a mixture of superabsorber and high surface area fibers and the like to provide the high liquid suction capability. These structures have, however, the disadvantage that the small capillaries limit the liquid permeability thus providing large flow resistance and slow rate for liquid being absorbed.
Hence, it is an object of the present invention to provide a liquid handling member which overcomes the problems posed by the prior art.
It is a further object of the present invention to provide a liquid handling member which exhibits a high liquid suction capability in combination with a high liquid permeability and/or a high absorbent rate.
It is a further object of the present invention to provide a device for handling body liquids comprising a liquid handling member which exhibits a high liquid suction capability in combination with a high liquid permeability and/or a high absorbent rate.
The present invention provides a liquid handling member to be used in a device for handling by liquids.
The liquid handling member is characterized in that said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) according to the capillary sorption test of at least 50 cm and said liquid handling member further having a liquid permeability of at least 5 Darcy preferably at least 10 Darcy, most preferably at least 20 Darcy according to the saturated liquid permeability test.
Attentively, the liquid handling member is characterized in that said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) according to the capillary sorption test of at least 80 cm and said liquid handling member further having a liquid permeability of at least 2 Darcy according to the saturated liquid permeability test.
Yet alternatively, the liquid handling member is characterized in that said liquid handling member has a capillary sorption absorption height at 50% of its capacity at 0 cm absorption height (CSAH50) according to the capillary sorption test of at least 80 cm and said liquid handling member further having an absorption time to 80% of its capacity of less than 5 seconds according to the Demand Absorbency Test disclosed herein.
The liquid handling member preferably has a capillary sorption absorption capacity at 100 cm absorption height of at least 5 g/g, preferably at least 10 g/g.
The invention further relates to absorbent structures, comprising a first region for acquisition/distribution of fluid and a second region for storage of fluid. The first region comprises at least one member for acquiring and/or transporting liquid whereas the second region comprises said liquid handling members.
The present invention further provides a device for handling body liquids comprising a liquid handling member or an absorbent structure according to the present invention. The present invention further relates to absorbent articles such as baby diapers comprising a liquid handling member or an absorbent structure according to the present invention.